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Biomedical subjects

S Hansen

Publications and source records attributed to S Hansen.

At least 253 records · Page 14Linked to original sources
PubMed1985

Hallervorden-Spatz disease: cysteine accumulation and cysteine dioxygenase deficiency in the globus pallidus.

We describe neurochemical abnormalities found in the brains of 2 patients with autopsy-confirmed Hallervorden-Spatz (HS) disease. In 1 patient, contents of cystine and of glutathione-cysteine mixed disulfide in the globus pallidus were markedly elevated above values for appropriate control subjects. Activity of cysteine dioxygenase, which converts cysteine to cysteine sulfinic acid, was reduced in the globus pallidus, but normal in the frontal cortex and putamen of both patients. gamma-Aminobutyric acid content was markedly decreased in the globus pallidus and substantia nigra of both patients. These results suggest that cysteine accumulates locally in the globus pallidus in Hallervorden-Spatz disease as a result of an enzymatic block in the metabolic pathway from cysteine to taurine. Accumulated cysteine may chelate iron, accounting for the local increase in iron content in Hallervorden-Spatz disease. The combined excess of cysteine and ferrous iron may generate free radicals that damage neuronal membranes to cause the typical morphological changes observed in this disorder.

Adult↗
PubMed1985

Behavioural similarities between mother rats and benzodiazepine-treated non-maternal animals.

Mother rats nursing large litters are hyperphagic, aggressive towards conspecifics, and show less freezing behaviour than non-maternal animals. These naturally occurring adaptations resemble those elicited by benzodiazepine treatment in virgin rats, indicating a common neurochemical change in the brains of mother rats and benzodiazepine-treated virgins. In line with this hypothesis, it was found that three functional benzodiazepine antagonists (FG 7142, pentylenetetrazol, caffeine) decreased food intake, lowered aggression and strengthened freezing in lactating mother rats. These psychopharmacological observations support the idea that GABA neurotransmission is enhanced during motherhood in the rat.

Aggression↗
PubMed1985

Use of the polyethylene glycol adduct of L-asparaginase for the treatment of hyperasparaginemia in a schizophrenic patient.

A man with hyperasparaginemia, presumably due to chronic deficiency of asparaginase activity, had been schizophrenic and unresponsive to antipsychotic drugs for at least 22 years. He was given repeated injections of bacterial L-asparaginase rendered relatively nonimmunogenic by covalent binding to polyethylene glycol (PEG). PEG-asparaginase lowered plasma asparagine concentrations from 4 to 5 SD above normal down to undetectable levels, and eliminated asparagine from the cerebrospinal fluid. Despite biochemical correction lasting at least 55 days, the patient did not improve psychiatrically. Experience limited to this single patient suggests that PEG-asparaginase therapy is relatively innocuous, but does not clarify whether there is an etiological relationship between hyperasparaginemia and psychiatric illness.

Adult↗
PubMed1985

Is a circulating neurotoxin involved in the pathogenesis of Huntington's chorea?

We tested the hypothesis that the premature neuronal death which occurs in Huntington's chorea (HC) might be the result of a genetically-determined enzymatic failure in the degradation of a circulating neurotoxin of either endogenous of exogenous origin. Infant rats were given daily subcutaneous injections of large quantities of whole serum (for 24 days), or of a concentrated serum ultrafiltrate (for 37 days), obtained from HC patients or control subjects. Animals were killed 4 months after the end of injections, and their striata were examined neurochemically. There was a significant but small (16%) reduction in the mean striatal content of gamma-aminobutyric acid (GABA) in rats treated with whole serum from HC patients, but no striatal GABA deficiency was observed in rats treated with ultrafiltrates of serum from HC patients. Nor did these rats have any reduction in their striatal choline acetyltransferase activity. We conclude that if a circulating neurotoxin does contribute to the pathogenesis of HC, it must either be a small molecule which is tightly bound to serum proteins, or less likely a large compound with a molecular weight greater than 10 000.

Animals↗
PubMed1985

Reduced fearfulness in the lactating rat.

The freezing reaction in response to a brief auditory signal was assessed in lactating and virgin rats. Freezing was markedly reduced in lactating animals, but only when their litters were present in the testing cage. Pup exposure did not shorten the duration of freezing in virgin animals. The reduced fearfulness in lactating females, as measured by the freezing response, may complement maternal aggression in the protection of the offspring.

Animals↗
PubMed1985

Interconversion of serine and glycine is normal in psychotic patients.

Fasting plasma serine and glycine concentrations, determined by ion-exchange amino acid chromatography, were similar in a large group of psychotic patients with various forms of schizophrenia and in healthy control subjects. Serine and glycine concentrations were also similar in cerebrospinal fluid of psychotic patients and control subjects. The contents of serine and glycine in autopsied brain of three patients with chronic schizophrenia did not differ from contents of these amino acids in control subjects when analyses were limited to brains frozen rapidly after death. These data do not support a recent suggestion (Waziri et al., 1984) that disturbed serine metabolism may be a biological marker and a vulnerability factor for psychosis.

Adult↗
PubMed1985

Capillary number and percentage closed in human diabetic sural nerve.

The number of capillaries per mm2, minimum intercapillary distance, number of endothelial nuclei per capillary section, and percentage of capillaries closed were evaluated in transverse sections of fascicles of 45 control and 36 diabetic sural nerves. All controls and patients were prospectively studied to ascertain their diabetic and neuropathic status. An index of pathology was introduced and it was found to provide a sensitive and reliable measurement of the presence and severity of neuropathy. The number of capillaries and minimum intercapillary distance of diabetic nerves were not significantly different from those of controls (P greater than 0.05). Diabetic nerves exhibited a small but statistically significant increase in the number of endothelial nuclei per capillary that was positively correlated with the severity of neuropathy. The most striking abnormality was the statistically significant increase in the percentage of capillaries closed in patients with neuropathy as compared to those without neuropathy and controls. Among diabetics, this percentage increased with the severity of neuropathy (P = 0.008). The two capillary abnormalities that have been demonstrated may play a role in the development of diabetic polyneuropathy.

Adult↗
PubMed1985

An improved automated method for the measurement of thermal thresholds. 1. Normal subjects.

Clinical tests of thermal sensation are poorly quantified and not strictly modality specific. Previous automated thermal testing systems have had limited usefulness with high intra-and inter-individual variability. This paper describes an automated thermal system (Glasgow system) which is an extensive modification of previous techniques to answer these criticisms. It comprises a microprocessor-driven Peltier element and utilises the forced choice method of psychophysical analysis to determine the thresholds to thermal stimulation. In a control group of 106 healthy subjects the mean heat threshold for the wrist was found to be 0.23 degree C (SD = 0.06 degree C) and the mean cold threshold 0.15 degree C (SD = 0.05 degree C). Repeated determinations showed a maximum of 5% intra-individual variation in comparison to previously reported values of up to 150%.

Adolescent↗
PubMed1985

An improved automated method for the measurement of thermal thresholds. 2. Patients with peripheral neuropathy.

Thermal thresholds were determined by a new technique, at wrists and ankles in 143 patients with peripheral neuropathies of diverse aetiologies. Ninety-nine percent of patients (141/143) had abnormalities of one or both thresholds. In only two patients with mild/early Friedreich's ataxia were thermal thresholds normal. Electromyography was performed and fastest motor nerve conduction velocities and sensory nerve action potential parameters were measured in all the patients using conventional techniques in ulnar, median and sural nerves. Eighty-nine percent of patients (127/143) had one or more abnormalities on these electrophysiological studies. However, 39 of 40 patients with completely normal sensory nerve studies had an abnormality of one or more thermal thresholds. Eighty-six percent of 48 patients with normal sural nerve studies had abnormal thermal thresholds at the ankle. Sixty percent of 70 patients with normal sensory median and ulnar nerve studies had abnormal wrist thermal thresholds. This improved technique for the determination of thermal thresholds reveals that disturbances of thermal sensibility are present in the majority of peripheral neuropathies irrespective of aetiology. In some patients disturbances of thermal thresholds antedate the appearance of abnormalities on conventional electrophysiological investigation. The findings suggest that this technique has considerable usefulness in the detection of small nerve fibre dysfunction in the context of generalised neuropathy.

Adolescent↗
PubMed1985

Electrophysiological studies in the post-viral fatigue syndrome.

Single fibre electromyography (SFEMG) was studied in 40 patients with the post-viral fatigue syndrome. These patients were also assessed clinically, serologically, virologically and immunologically. About 75% of the patients had definitely abnormal SFEMG results. This was regarded as evidence of abnormality in the peripheral part of the motor unit. The muscle fibre was the likely site of involvement.

Adolescent↗
PubMed1985

Sensory involvement in motor neuron disease: further evidence from automated thermal threshold determination.

Thermal thresholds were determined in 40 patients with motor neuron disease and in 40 age- and sex-matched healthy subjects. The thermal thresholds were estimated on the skin of wrist and ankle using an automated microprocessor controlled system and the "two alternative forced-choice method" of psycholphysical analysis. Abnormalities of thermal thresholds (greater than or equal to 99th percentile) were seen in 80% of the motor neuron disease patients. The results are in agreement with reports of sensory pathway involvement in the literature. Thermal threshold abnormalities are common in motor neuron disease and indicate the involvement of the small fibre afferent pathways.

Adult↗
PubMed1985

Brain amino compounds in a Huntington's disease patient on isoniazid therapy.

We describe biochemical abnormalities in autopsied brain of a patient with early Huntington's disease (HD) who died of pentobarbital overdosage while under treatment with isoniazid (INH). The brain contained hydrazine, a terminal metabolite of INH, which inhibits gamma-aminobutyric acid (GABA) aminotransferase. GABA content in the basal ganglia was higher than expected for HD, and GABA content was supranormal in some brain regions. Homocarnosine (GABA-histidine) content was greatly elevated in all brain regions, suggesting chronic GABA elevation in life. Therefore, the increase in brain GABA content observed in experimental animals given INH or hydrazine also occurs in human patients.

Adult↗
PubMed1985

Oxytocin and sexual behaviour in the male rat and rabbit.

In male New Zealand white rabbits, it was shown that oxytocin but not vasopressin concentrations in plasma were markedly raised after ejaculation. In male Wistar rats, oxytocin infused into the internal carotid artery reduced the number of intromissions made before ejaculation but had no other significant effect. Infusion of oxytocin into the third ventricle increased the latencies to the first mount and intromission and lengthened post-ejaculatory refractory periods. It is suggested that oxytocin released into the periphery during coitus, while not essentially involved in ejaculation, may exert effects on the genital periphery. Behavioural effects of centrally administered oxytocin suggest that it may play a role in the neural mechanisms underlying post-ejaculatory refractoriness.

Animals↗
PubMed1985

[Tetrasomy 9p].

A newborn male with multiple malformations and an extrachromosome is presented. The cytogenetic study of peripheral blood lymphocytes revealed tetrasomy 9p: 47,XY, + t(9;9)(pter----q13::p11----pter). The C-banding pattern provided evidence for maternal origin of the extrachromosome. Tetrasomy for the short arm of chromosome 9 is a very rare condition; reports about only ten further patients have been found in the literature. The phenotypic expression resembles trisomy 9p, but tetrasomy 9p has more severe additional malformations.

Abnormalities, Multiple↗
PubMed1984

Elevation of gamma-aminobutyric acid in human brain may increase dopaminergic neuronal function.

Studies in experimental animals have yielded conflicting findings as to the influence of gamma-aminobutyric acid (GABA) on the activity of nigrostriatal and mesolimbic dopaminergic neurons. We measured cerebrospinal fluid (CSF) concentrations of GABA and homovanillic acid (HVA) in 19 patients before and during treatment with isoniazid. CSF GABA concentrations increased markedly during isoniazid administration, presumably reflecting increases in brain GABA content. At the same time, HVA concentrations in CSF rose significantly. The net effect of elevating brain GABA content in humans appears to be to increase dopamine release from dopaminergic neurons.

Brain↗
PubMed1984

Intravenous versus intracoronary streptokinase therapy for acute myocardial infarction in community hospitals.

A consecutive series of 184 patients with acute myocardial infarction (AMI) received thrombolytic therapy. The first 63 were treated in the catheterization laboratory with intracoronary streptokinase (IC-STK), and 44 (70%) had successful thrombolysis. One hundred twenty-one patients received intravenous (IV) STK immediately after diagnosis of AMI, and 99 (82%) were found to have an open infarct artery. Only 58% of patients (14 of 24) who required transfer from out-of-town hospitals for IC-STK treatment had successful thrombolysis; in contrast, IV-STK given in the local hospital resulted in an 85% (72 of 85) rate of thrombolysis (p = 0.005). IV-STK thus appears at least as effective as IC-STK for AMI and is more effective for patients treated in hospitals without catheterization facilities.

Aged↗
PubMed1984

Spinal monoaminergic modulation of masculine copulatory behavior in the rat.

The sexual behavior of male rats receiving infusions of 5-HT, dopamine and noradrenaline intrathecally in the spinal cord of intracerebroventricularly (i.c.v.) in the lateral ventricle was observed. Intrathecal infusions of 5-HT and noradrenaline inhibited penile insertions and ejaculation, noradrenaline being the more potent of the amines. Dopamine was without effect. I.c.v. amine infusions impaired to various extents the masculine mating pattern, primarily by interfering with the males' tendency to approach the females. The facilitation of mating seen after intrathecal administration of the aminotetraline, 8-OH-DPAT, was more pronounced than that observed following its i.c.v. infusion.

8-Hydroxy-2-(di-n-propylamino)tetralin↗